Fuel pump not running after I shorted out nc contacts in fuel pump relay

[j72x1]

The pump is a 2 pin connector.i connected a multimeter earth to earth and positive to positive, so the pump must be faulty?
From comments by other members it's likely I have destroyed the ecu
I am confused about the following.this morning I connected a 12 volt voltage from the cigar lighter to the fuel pump connector.i know the resistance of the fuel pump is 9 ohms and it is not shorting to earth.why did the pump not run under these conditions? Terry

 

[thomp1983]

To manually activate just the pump you'd need to supply 12v and an earth to it, I'm guessing you took the 12v from the cigarette lighter and probably didn't fit an earth.

To test your ecu get yourself a test light or 12v led, connect it to the 2 pin connector, make sure the fuel pump relay is fitted and try to start the car, the light/led should light, if your using an led and it doesn't light turn the led around in the connector as there polarity sensitive

 

[j72x1]

I used an old cigar lighter lead from a tyre inflater so it had a 12 volt positive and an earth.i am learning something new.i have a test light, and will connect it to the 2 pin connector to test the ecu.thanks for that Terry

 

[carmanmemoranda]

I keep reading this thread and I'm still not sure what you were attempting, or why.

But it appears you now have other problems to sort before even getting back to your original issue.

What was the issue ?

 

[jj4091]

Answer to post 15
Because it is goosed, if you got the polarity right when you connected it that is. Have you actually taken the pump out of the tank or is it an external one

 

[flameport]

If that has not blown then the ecu is buggered.is there any way i can confirm it needs replacing?

The fuel pump connector has 2 pins, one is permanently connected to ground, the other one will be 12V when the fuel pump is running.

Using a meter or test probe you need to confirm that:
one pin of that connector is connected to ground
the other pin has 12V on it with the ignition on, and nothing with the ignition off.

If it never has 12V, then either the ECU has failed, the relay has failed, or the fuse is blown.
If it always has 12V even with the ignition off, then it's likely the ECU has failed, less likely is the relay contacts have welded together.

this morning I connected a 12 volt voltage from the cigar lighter to the fuel pump connector

Are you certain you connected to the part of the connector attached to the fuel pump wires, and not to the other half which is connected to the wiring harness?

 

[j72x1]

I can follow these instructions, they are very precise, and they will tell me what I need to know ie do I need to replace the ecu.many thanks.
Also I am certain I connected the wires to the the top of the fuel pump which is integral to the fuel pump. and not to the part that forms part of the wiring harness

 

[j72x1]

Answer to post 15
Because it is goosed, if you got the polarity right when you connected it that is. Have you actually taken the pump out of the tank or is it an external one

 

[j72x1]

The fuel pump is inside the petrol tank and it has never moved from that position Terry

 

[jj4091]

The fuel pump is inside the petrol tank and it has never moved from that position Terry

I asked if you are sure you had the polarity correct when you connected it as it probably would not run if it was reversed. If you take the pump out you may find somehing that is repairable.

 

[j72x1]

Sorry my bad.polarity was correct.black wire to earth,the other wire to positive

 

[MeldrewsMate]

Terry, if you're worried you have destroyed the ecu then do a simple test...
Pull out the fuel relay.
Switch on the ignition so that you would expect the fuel pump to run.
Insert the fuel relay and listen/feel for the relay energising. If unsure try with a proven relay.

If it clicks/energises then you haven't destroyed THAT part of the ecu.

 

[j72x1]

Hello m m
My first post was 13 8 25. at that time the tank was one quarter full . the fuel gauge today was half way down the red completely empty mark.
About a week ago a scrap dealer walked by.i did not want to sell the micra, so he left a card for if I change my mind.
The tank filler cap is not damaged.he must have come back and stolen my petrol.the only way he could do that is using the fuel pump in the tank.
So the fuel pump had to be working about a week ago.
I now need to get 5 litres of petrol and think what to do next Terry